We can first calculate all the possible sums and then determine the set of possible outcomes.
Possible sums are:
1+2 = 3
1+4 = 5
1+6 = 7
1+8 = 9
2+2 = 4
2+4 = 6
2+6 = 8
2+8 = 10
3+2 = 6
3+4 = 7
3+6 = 9
3+8 = 11
4+2 = 6
4+4 = 8
4+6 = 10
4+8 = 12
From the above possibilities, the outputs would belong to the set:
{3, 4, 5, 6, 7, 8, 9, 10, 11, 12}